<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
    <script>
        $(document).ready(function() {
            $('#user').blur(function() {
                $.post('./jquery.php', {
                    user: 'zs',
                    pwd: '123'
                }, function(data) {
                    console.log(data);
                });
            })
        })
    </script>
</head>

<body>
    <form action="">
        用户名:<input type="text" name="username" id="user">
        <span id="info"></span><br>密码:
        <input type="text" id="pwd">
        <input type="button" value="注册" id="btn">
    </form>
</body>

</html>